The present invention relates to wooden structures and metal connectors for joining wooden members to form the wooden structures such as in the construction of wooden joists for enabling such wooden structures to be used to support structural loads.
In constructing various types of wooden truss assemblies, including both certain types of roof trusses and floor joists, it has been common to use large wooden structural members, e,g. wooden members having a width of at least 10 inches. Such large wooden members, however, are becoming increasingly difficult to find and as a result have tremendously increased in cost. Consequently various alternatives have been sought for enabling the construction of such trusses employing more commonly available wooden members such as 2 by 4 wooden strips. In seeking to find such alternatives there have been two primary criteria that had to be met. First, the alternative devices had to be able to withstand large compressive loads so that the trusses that were constructed could be used for bearing substantial structural loads. Secondly, it was considered desirable to develop alternative devices that could be prefabricated at a manufacturing plant and then easily shipped to a building site without a high degree of risk of incurring damage to the truss structures.
Three types of devices that have been developed for prefabricating such structural trusses are illustrated in U.S. Pat. Nos.: 3,025,577 to Jureit; 3,298,151 to Jureit and 4,078,352 to Knowles. Each of these patents illustrates a metal web member stamped out from a piece of sheet metal with the web member having at least one leg with connector plates at both of the extremities of such leg.
The two patents to Jureit both illustrate metal web members having a single leg with connector plates at both extremities of the leg. Each of the connector plates has a plurality of teeth that are stamped out from the plate which teeth are then embedded in the wooden members that are to be interconnected by the web member.
The patent to Knowles discloses a V-shaped metal web member having connector plates both at its apex and at the extremity of the two legs of the V-shaped member. Each of the legs has extending along substantially its entire length a rib that extends outwardly from the leg and side flanges extending in the opposite direction as the rib. Each of the connector plates in this web member has a plurality of teeth that are struck out from the plate with these teeth extending in a direction opposite the direction in which the rib along each leg extends. The web members disclosed by this patent to Knowles are used in prefabricating truss assemblies at a manufacturing plant with such assemblies then being shipped to a building site. Due to the existence of the projecting ribs, the truss assemblies along their lateral sides are not entirely flat which leads to problems when shipping such assemblies. The existence of the ribs that project outwardly from the truss assemblies creates two undesirable problems. First, the projecting ribs limit the number of trusses that can be packed in the transporting vehicle. The projecting ribs also have a tendency during shipping to bang against the adjacent truss assemblies thereby often causing damage to such assemblies. While such problems have existed, in accordance with the teachings of the patent to Knowles it has been believed that it was mandatory to incorporate such ribs extending in the opposite direction as the teeth and the flanges as disclosed by such patent in order to provide sufficient compressive strength to the legs of the V-shaped web member.